The present invention relates to throwing wheels of the type used for abrasive blast cleaning or peening wherein a throwing wheel includes a plurality of throwing vanes mounted upon a runnerhead in a vane receiving channel. Such throwing vanes must be locked in the runnerhead against the action of centrifugal force during high speed rotation. More particularly, the invention relates to a unique improvement of the vane locking apparatus shown in FIGS. 23-30 in U.S. Pat. No. 3,241,266 which was granted to Joseph E. Bowling, Jr., on Mar. 22, 1966.
The vane locking mechanisms of the prior art, as exemplified by U.S. Pat. No. 3,241,266 properly perform the function of locking the throwing vanes in the runnerhead. However, a very serious disadvantage of the prior art is inherent in the fact that particles of grit, abrasive throwing media and the like cause the locking pins to jam in the locking pin hole and creates a serious problem during maintenance of the throwing wheel. As is well known, the throwing vanes are subjected to highly abrasive actions during operation and it becomes necessary to replace the throwing vanes either weekly, daily or sometimes hourly. There have been occasions when the locking pins have become so jammed that it takes five to seven minutes of frustrating effort to remove the locking pin so that a worn out throwing vane can be replaced.